关键词: 动态材料模型, 功率耗散系数, 加工图, 流变失稳, 有限元, 视觉传感, 受控脉冲穿孔, 等离子弧焊, 控制

Abstract: The workability consists of two independent parts: state-of-stress (SOS) workability and intrinsic workability. The traditional processing maps proposed by PRASAD on the base of dynamic material model (DMM) only indicate the intrinsic workability dependent on the material properties. A new three-dimensional processing map including strain is built, which describes the variations of power dissipation coefficient and flow instability domains with strain rate, temperature and strain. For metals with typical strain softening such as magnesium alloy, this new three-dimensional processing map has solved the sensitivity of the elevated workability to strain. By combination of the processing map with finite element simulation, the distribution and variation of stress, strain, strain rate, temperature and flow instability domains are obtained under certain thermal deformation conditions. This method can be considered as an effective way to analyze the workability of metals in the whole processes of hot deformation.

Key words: Dynamic material model, Finite element simulation, Flow instability, Power dissipation efficiency, Processing map, Control system, Controlled pulse keyholing, Vision-observation, Plasma arc welding